Method of and apparatus for treating grease



H; M. FRASER 2,257,945

METHOD OF AND APPARATUS FOR TREATING GREASE Oct. 7, 1941.

Filed May 24, 1940 Patented Oct. 7, 1941 METHOD or m arrsns'rus roa TREATING GREASE} Harold M. Fraser, New Orleans, La., assignor to International Lubricant Corporation,

New

Orleans, La, a corporation of Louisiana Application May 24, 1940, Serial No. 337,097

. 13 Claims.

The present inventlonrelates to the treatment of grease, and more particularly to a method and apparatus for mixing greases and removing entrapped air therefrom.

Usually one of the final steps in the manufacture of greases is the pouring of the same into pans so that the grease may chill. This results in rather stiff blocks, the contents of which need further treatment or milling to produce a final grease-of proper texture and consistency, that is, one which forms a smooth, homogeneous mass.

The working or milling of the grease mixes and entraps air into the grease, which it is highly desirable to remove.

The removal of air from greases has the following advantages:

(1) The storage stability of the grease is system being lubricated;

, (3) If air bubbles are present in grease, when the latter is used to lubricate bearings, the entrapped air displaces a definite quantity of grease which may be necessary for the lubrication oi the bearing.

1 The present invention will be described in connection with the accompanying drawing, in

which Figure lis an elevational view, partly diagram- ,matic, of apparatus suitable for carrying out the present invention Fig. 2 is a plan view ofv the upper air-exit plate; Fig. 3 is a plan view of the lower air-exit plate; and Fig. 4 is a plan view of the grease divider,

facilitating the removal of the air from the grease on the entrance of thelatter into the vacuum grease container.

Referring to the drawing, grease which has been preferably cooled" to room temperature in g pans is delivered to a hopper 5, adapted to hold between 500-600 pounds of grease. The grease is whereby the grease is broken up in small streams,

conveyed by means of a conveyor, preferably a screw conveyor 2, located at the bottom of hopper I, to a pump 3 which forces the grease through conduit 5 and'sc'reen 5 in container 6. The grease then travels by conduit I to T 8,

where it is divided in two streams 9 and i0,,re-"

spectively, which are forced into opposite ends II and I! of the mixer it.

The conveyor 2, rotating at about 120 R. P. M.. removes the grease from the hopper at the rate of about 200-300 pounds per minute. These speciflcations are illustrative, and not by way of limitation. The screen 5 is an exceedingly fine one being preferably a mesh screen.

. The mixer i3 is provided with a series-oi perforated plates i4 and I5, preferably arranged so that the grease may travel around the end of 88.011. plate in a wave motion to ensure a more thorough mixing of the grease. Plates II are open at their tops and plates ii are open at their bottom portions, these plates alternating one with the other to impart a wave motion to the grease. The arrangement is especially desirable when two or more diflerent types of grease are mixed together, as for example, a soda base grease with an aluminum, calcium or lead soap grease.

The grease is pumped from the mixer II through conduit It to vacuum tank I I, which usually has a vacuum varying between 26 to 30 inches of mercury. The grease enters the vacuum pipe through grease divider plate It, which is provided with apertures l9, which may range in size from A; of an inch to of an inch or thereabouts. Using a plate 16 inches in diameter about 260 inch apertures may be provided. The plate it functions to break the incoming grease into small'streams, which enables the entrapped air to be quickly removed. Each bubble of air as it comes into the divider plate is surrounded by a thin film of grease which breaks upon'the grease entering the vacuum tank, and the air is removed from the grease. The air is withdrawn from the vacuum tank ll through conduit 20 by means of vacuum pump it. The finished grease at the conclusion of a run is removed ,from the tank H by the pump 29, the

grease passing through exit conduit 28.

It is to be noted that the vacuum tank H is provided with an upper air exit plate 124 and a lower plate 25, these plates being provided with apertures 26 and Ti, respectively. The tank i'l being under vacuum, there is a tendency for the grease therein to foam or be lifted. If there is a sumcient amount of space above the active grease line, there is relatively little tendency for vacuum pump 2!. If the grease does foam up to the level of plates 24 and t5, thelatter act as barriers preventing the'grease from passing into suction conduit 20, while permitting the air to pass therethrough.

The vacuum tank I1 is adapted to hold between 35,000 to 40,000 pounds of grease which is approximately one days production. Therefore, in

' carrying out the present invention, the mixing and milling of the grease is continuous for the period of one day, or for a shorter period if so desired. After the vacuum tank has been operating until it contains a charge of the character set forth, the grease is allowed to remain in the vacuum tank for a period of two to ten hours, depending upon the consistency of the grease. During this period, the vacuum pump 2| is operating to remove volatiles from the grease and also any remaining traces of air. After the grease has been allowed to stabilize for a period of two-to ten hours, vacuum pump 2| is stopped and the vacuum is broken. Then the pump 29 is started, and the grease is removed from the tank by passage through the conduit 28. The grease may then be passed into proper containers.

The grease which is the subject matter of the present invention is, of course, made by mixing a metal soap with mineral and/or vegetable oils, there being optionally present other ingredients.

While the present invention may be used for V the treatment of various kinds of greases, it is particularly applicable to the production of grease made in accordance with the disclosure of application Serial No. 347,533.

While it is not desired to be limited t the conditioning of grease of any particular viscosity, it may be stated that the viscosity of the grease which is usually delivered to the vacuum tank I! at atmospheric temperature does have a slight bearing upon the removal and elimination of the air from the grease. If the A. S. T. M. worked penetration 'of the grease is harder than 250, it is necessary to pump the grease into the vacuum tank I! at a much slower rate, and to leave the grease in the tank somewhat longer than Specifled, as for example where the grease would ordinarily be left in the tank from two to ten hours, if a hard grease is pumped into the vacuum tank the grease would be left therein for a period of two to twelve hours. Further, upon conditioning a grease made with a high viscosity oil, as for example above 100 Saybolt at 210 F. and having a penetration between 325 and 375, itis necessary to slow down to some extent the pumping of the grease.

The method andapparatus herein disclosed has produced exceedingly good results when it has been used to treat and condition a grease having approximately an oil viscosity of 85 Saybolt at 210 F., the grease containing 4% soap"; the grease being a mixture of 75% of a soda base grease and 25% of an aluminum base grease.

In carrying out the present invention, the sodium soap grease and the alumnium soap grease. which has been cast in pans, are introduced into the hopper I in approximately the ratio of three parts of soda base grease and one part of aluminum base grease. The grease is then pumped through the screen 5 to break the grease up into a smooth homogeneous mass. The screen serves to increase the homogeneity of the grease. After the grease passes through the mixer I3, and by the time it is ready to be introduced int the vacuum tank II, the grease is a homogeneous smooth transparent product, and as it leave the vacuum tank it contains no visible traces of entrapped air.

The method and apparatus herein disclosed continuously produces from diflerent soap base greases a well mixed smooth grease, and analyses of the grease taken at relative intervals as it comes from the vacuum tank, shows that on a ten gram sample the proportions of the different soap base greases are then within about one-half of one percent of the proportions in which they are charged into the hopper. For example, when there is initially charged three parts of a soda base grease and one part of an aluminum base grease, the finally conditioned grease as it is removed from the vacuum tank has the different soap base greases present in that proportion.

The method and apparatus herein set forth functions admirablyto condition greases which have been poured into pans for cooling and which are usually too stifl to be used for ordinary lubrication. It is quite desirable to mill the greases to impart to them the proper texture and consistency. When this is done, the working or milling of the lubricating grease in the working and mixing apparatus herein set forth functions to introduce air into the grease which frequently is highly objectionable. While themixing and milling apparatus herein set forth which is thought to be highly novel, does produce a grease from which it is desirable to remove'the air, it is desired to point out that greases may be milled in other types of apparatus which causes air to be entrapped in the grease, and therefore greases, irrespective of the method of milling, r whether they have at all been milled, may be treated in the vacuum tank by splitting them up into fine streams. Then each bubble of air is surrounded by a thin film of grease, and as soon as each stream comes in contact with a vacuum, the film of grease breaks and the air is removed from the grease.

It is desired to point out that if the air is left in the grease the grease in many occasions tends to become milky white, and this is particularly so when the grease with its air content is passed.

through a grease gun.

The present invention is applicable to the production of greases of various types, including cup greases and pressure gun greases.

In accordance with the present invention, there is thereby produced, as a new product, lubricating grease substantially devoid of air and resistant to oxidation. a

From the standpoint of the apparatus, the m vention resides broadly in means for feeding the grease to a hopper or other mixing means, means for separating the grease into separate portions, a mixer provided with a series of baffles positioned to pass the grease through the mixer in an impeded path, as for example a tortuous path or a sinuous path; a vacuum container for receiving the grease from the mixture, means for feeding the grease to the vacuum container, and means for withdrawing the grease from the latter.

While the present method and apparatus is articularly useful in producing a mixed soap base lubricating grease, it may be stated that the apparatus may be used for the milling and conditioning of any grease which is ordinarily too stiff to be used for lubricating purposes. In

other words, instead of feeding into the hopper I a. mixture of a soda base grease and an alu1m-' num base grease, a soda base grease or a calcium base grease, or any other grease may be fed into the hopper and passied through the system sential to split the grease into two components when the grease which is being-conditioned has not been compounded by mixing .a grease having one soap base with a grease having a difierent soap base. In other words, a soda base grease by itself or a calcium base grease by itself or a similar grease may be delivered directly from the hopper to the mixer I3.

I claim:

l. The method of removing entrapped air from lubricating grease comprising dividing the grease into a plurality of small streams containing entrapped air, and subjecting the so-treated grease to a vacuum whereupon the air is quickly removed from said grease streams. I

2. The method of removing entrapped air from lubricating grease comprising dividing the grease into a plurality of small streams containing entrapped air, introducing said streams of grease into a vacuum container whereupon the air is quickly withdrawn from the streams of grease,

and withdrawing the removed air from the vacuum container.

3. The method of removing entrapped air from lubricating grease comprising dividing the grease into a plurality of small streams containing entrapped air, introducing said streams of grease into a vacuum container whereupon the air is quickly withdrawn from the streams of grease, withdrawing the removed air from the vacuum tank while preventing the withdrawal of grease along with the air, and separately withdrawing the so-conditioned grease.

4. The method of removing trapped air from lubricating grease comprising introducing the grease into a vacuum container, dividing the grease into small particles containing air bubbles covered by films of grease, subjecting the soconditioned grease to the action of a vacuum to break the grease films, and removing the freed air from the vacuum container.

5. The method ofremoving trapped air from lubricating grease comprising introducing the grease into a vacuum container, dividing the grease into small particles containing air bubbles covered by films of grease, subjecting the so-' conditioned grease. to the action of a vacuum to' break the grease films, removing the freed air from the vacuum container, allowing the grease charge to build up in said vacuum container,

further removing from said grease charge any remaining traces of air, and then removing the stabilized grease.

6. The method of removing trapped air from lubricating grease comprising introducing the grease into a vacuum container, dividing the grease into small particles containing air bubbles covered by films of grease, subjecting the soconditioned grease to the action of a vacuum to break the grease films, and removing the freed air from the vacuum container while preventing freed air from the vacuum container, and meansfor withdrawing the grease therefrom.

8. In apparatus for the production of a smooth homogeneous mixed grease from a plurality of different soap base greases, the combination of grease feeding means, means for separating the grease into separate portions, a mixer provided with a series of baiiies positioned to pass the grease through the mixer in an impeded path, a vacuum container for receiving the grease from the mixer, means for feeding the grease to the vacuum container, means therein for dividing the grease into particles containing air bubbles covered by films of grease adapted to break upon being subjected to the action of a vacuum, means for removing the freed air from the vacuum container, and means for withdrawing the grease from the container,

9'. In apparatus for the production of a smooth the vacuum container, means therein for di-' viding the grease into particles containing air bubbles covered by films of grease adapted to break upon being subjected to the action of a;

vacuum, means for removing the freed air from the vacuum container, and means for withdrawing the grease from the container.

10. In apparatus for the production of a smooth homogeneous mixed grease from a plurality of diiferent soap base greases, the combination of grease feeding means, a mixer, means for splitting the grease into two components and delivering one component to one end of the grease mixer and the other component to the other end of the grease mixer, said mixer being provided with a series of baiiles positioned to pass each component of the grease through the mixer in an impeded path, a vacuum container, means for uniting'and delivering the so-treated'grease to the vacuum container, means therein for breaking up the grease in a plurality of fine streams facilitating the withdrawal of entrapped air, means for withdrawing the removed air from the vacuum container, and means for withdrawing the so-conditioned grease.

11. In apparatus for the production of a smooth homogeneous mixed grease from a plurality of different soap base greases, the combination of grease feeding means, means for initially subdividing the grease to increase its hogomeneity, means for separating the grease into separate portions, a mixer provided with a series of apertured baflles positioned to pass the grease through said mixer in an impeded path, a vacuum container for receiving the grease from the mixer, means for feeding the grease to the vacuum container, means therein for dividing the grease into particles containing air bubbles covered by films of grease adapted to break upon being subfor delivering the grease from themixer to the and means for withdrawing the grease from the container.

12. In an apparatus for the production of a smooth homogeneous mixed grease from a plurality of different soap base greases, the combination of grease feeding means, means for initially subdividing the grease to increase its homogeneity, means for separating the grease into separate portions, a mixer provided with a series of apertured baflles positioned to pass the grease through said mixer in an impeded path, a vacuum container, means for feeding the grease from the mixer to the vacuum container, means therein for breaking up the grease in a plurality of fine streams facilitating the removal of entrapped air, means for withdrawing the removed air from the. vacuum container, and means for withdrawing the so-condition'ed grease.

13. In apparatus for the production of a smooth, homogeneous grease, the combination of a mixer provided with means to pass grease therethrough in an impeded path, a vacuum container, means for delivering the grease from the mixer to the vacuum container, means in the latter for dividing the grease into particles containing air bubbles covered by films of smooth substantially homogeneous grease, vacuum means adapted to break said films of grease and to remove the freed air from the vacuum container, means therein for preventing the withdrawal of grease along with 5 the freed air, and means for, separately withdrawing the so-conditioned grease.

HAROLD M. FRASER. 

